JPH0464279A - Multilayer thin film wiring board - Google Patents

Abstract

PURPOSE:To further increase the density of a board by setting signal propagation delay time arbitrarily without installing a useless dummy gate or an extended wiring layer to said wiring layer. CONSTITUTION:A mesh hole 10 on a ground layer 2 installed in contact with a dielectric board 1 is enlarged arbitrarily in conformity with signal propagation delay time to be adjusted by the first wiring layers 4 and 5 on the upper part layer. If the hole size is enlarged arbitrarily in response to the signal propagation delay time, the permittivity around the X and Y wiring layers 4 and 5 will be increased under the effect of the dielectric board 1 whose relative permittivity is larger than that of synthetic resin layers 3a to 3c, and 7a and 7b, which makes it possible to set the signal propagation delay time in response to the size of the mesh hole 10 and enhance the density of the board.

Description

[Detailed Description of the Invention] [Summary] Regarding a multilayer thin film wiring board, it is possible to arbitrarily set the signal propagation delay time without using a dummy gate extension wiring layer for adjusting the signal propagation delay time of the wiring layer. With the aim of achieving higher density, a mesh-like ground layer is provided on a dielectric substrate with a large dielectric constant, and X, Y
A wiring layer is provided, and a metal layer is placed on the wiring layer via a synthetic resin layer.
In a multilayer thin film wiring board in which a ground layer in the form of a groove is provided, and X and Y wiring layers are similarly provided in multiple layers on the ground layer via a synthetic resin layer, the ground layer is provided in contact with the dielectric substrate. Make the mesh hole in the ground layer arbitrarily large according to the signal propagation delay time to be adjusted in the first X, Y wiring layer above it, or adjust the first X, Y wiring layer on the dielectric substrate. The mesh holes of the ground layer are provided at arbitrary positions corresponding to the signal propagation delay time.

[Industrial Application Field] The present invention relates to a multilayer thin film wiring board, mainly a multilayer polyimide thin film wiring board in which the insulating layer (dielectric layer) is a polyimide layer.

In general, a multilayer polyimide thin film wiring board has a mesh-like ground layer formed with mesh holes for venting gas on a ceramic substrate, and an X wiring layer in the X direction and an A Y wiring layer in the Y direction is provided, the X wiring layer and the Y wiring layer are connected by vias, a mesh-like ground layer is provided on the X and Y wiring layers via a polyimide layer, and a similar ground layer is provided on the ground layer. This is a multilayer thin film wiring board in which an X wiring layer in the X direction and a Y wiring layer in the Y direction are provided in multiple layers with polyimide layers interposed therebetween.

[Conventional technology]

By the way, in a conventional logic circuit as shown in FIG. 10, when two LSIs 31 and 32 are connected to RAM 30,
If the length of the wiring layer between the LSI 30 and the LSI 32 is different, the signal propagation time will be different. Therefore, the propagation times of the data ■ propagated from the LSI 3 ] and the data ■ propagated from the LSI 32 are different, and the data ■ and the data ■ do not arrive at the RAM 30 at the same time. Therefore, data (2) and data (2), which should be written to the RAM 30 at the same time, cannot be written to the RAM 30.

Therefore, in order to match the data ■ from LSI 31 and the data ■ between LSI 32, RAM 30 and LSI 31
A dummy gate 33 or an extension wiring layer 34 is provided in the intervening wiring layer to adjust the signal propagation delay time.

[Problems to be Solved by the Invention] However, with the above-mentioned multilayer thin film wiring board, it is not possible to eliminate the difference in signal delay time between the above-mentioned devices, and the R
It is necessary to provide a useless dummy gate 33 or an extension wiring layer 34 in the wiring layer between the AM 30 and the LSI 31, making it difficult to increase the density of the wiring board.

The present invention has been made in view of the above, and eliminates the need to provide unnecessary dummy gates or extension wiring layers in the wiring layer.
It is an object of the present invention to provide a multilayer thin film wiring board that can achieve higher density by arbitrarily setting the signal propagation delay time.

[Means to solve the problem] FIG. 1 shows a basic configuration diagram of the present invention.

In order to achieve the above object, the present invention has a structure in which a mesh-like ground layer 2 is provided on a dielectric substrate 1 having a large dielectric constant, and on the ground layer 2, X, A Y wiring layer 4.5 is provided, a mesh-like ground layer 6 is provided on the wiring layer 5 via a synthetic resin layer 3C, and an XY In a multilayer thin film wiring board in which wiring layers 8 and 9 are provided in multiple layers, the mesh hole 10 of the ground layer 2 provided in contact with the dielectric substrate 1 will be adjusted in the first wiring layer 4 and 5 above it. It is arbitrarily increased according to the signal propagation delay time.

Another configuration of the present invention is that a mesh-like ground layer 2 is provided on a dielectric substrate 1 having a large dielectric constant, and an X wiring layer 4. 5
A mesh-like ground layer 6 is provided on the wiring layer 5 via the synthetic resin layer 3C, and an x,
, 9 are arranged in multiple layers, the first X, 10 was provided at any position where the number 10 is formed.

[Function] The mesh hole size of the mesh-like ground layer provided in direct contact with the dielectric substrate can be arbitrarily adjusted according to the signal propagation delay time to be adjusted in the first X and X wiring layers above it. If the mesh hole is made larger, the relative dielectric constant around the X and Y wiring layers will be higher due to the effect of the dielectric substrate, which has a higher dielectric constant than the synthetic resin layer, and the signal propagation delay will depend on the size of the mesh hole. It becomes possible to set the time arbitrarily.

In addition, if the first X, Under the influence of the dielectric substrate, which has a higher dielectric constant than the resin layer, the relative dielectric constant around the χ and Y wiring layers similarly increases, and the signal strength increases depending on the area of the wiring layer that intersects with the mesh hole. It becomes possible to arbitrarily set the propagation delay time.

[Example] Hereinafter, an example of the multilayer thin film wiring board of the present invention will be described with reference to FIGS. 2 to 7.

In FIG. 2, 11 is a dielectric substrate with a large dielectric constant;
For example, it is made of a ceramic substrate. A mesh-like ground layer 12 is provided on the dielectric substrate 11 made of a ceramic substrate.
is provided. In the mesh-like ground layer 12,
As shown in FIG. 3, large oval mesh holes 13 are formed.

The mesh holes 13 are made of synthetic resin layers 14a14b, 14c made of polyimide provided on the ground layer 12.
The dielectric substrate 1 has a large dielectric constant around the wiring layer, and also serves as a hole for releasing gas contained therein.
1, its size is approximately several times larger than that of a mesh hole 19 in a mesh-like ground layer 18 provided above, which will be described later. Further, as shown in FIG. 4, on the mesh-like ground science 2, an X wiring layer (first wiring layer) 15 is provided which extends in the X direction through a synthetic resin layer 14a made of, for example, a polyimide layer. . X
On the wiring layer 15, as shown in FIG. 5, an X wiring layer (second wiring layer) 16 is provided which extends in the X direction via a synthetic resin layer 4b made of a polyimide layer. The X wiring layer 15 and the X wiring layer 16 have vias 17 as shown in FIG.
connected with. A mesh-like ground layer 18 is provided on the X wiring layer 16 via a synthetic resin layer 14c made of a polyimide layer. The mesh-like ground layer 18 includes a synthetic resin layer 20a made of a polyimide layer provided on the ground layer 18, as shown in FIG.
An elliptical mesh hole 19 of a normal size is formed for venting gas contained in the tube 20b. This mesh hole 19 is a hole only for venting gas, and is smaller than the mesh hole 13 of the mesh-like ground layer 12. Then, a mesh-like ground layer 18
An X wiring layer (third wiring layer) 21 is provided thereon, extending in the X direction via a synthetic resin layer 20a made of a polyimide layer, and further extending in the X direction via a synthetic resin layer 20b made of a polyimide layer. An X wiring layer (fourth wiring layer) 22 is provided.

According to this multilayer polyimide thin film wiring board, the synthetic resin layers 14a and 14b are made of polyimide layers.

Since the mesh hole 13 of the mesh-shaped ground layer 12 provided directly on the dielectric substrate ll made of a ceramic substrate with a larger dielectric constant than those of 14c, 20a, and 20b is made larger than the normal mesh hole 19, the dielectric constant X wiring layer (first wiring layer) due to the influence of the large dielectric substrate 11
The dielectric constants of the Y wiring layer 15 and the Y wiring layer (second wiring layer) 16 and the surrounding dielectric become high, and the signal propagation delay time can be set arbitrarily. Then, the size of the mesh hole 13 of the ground layer 12 is adjusted to the size of the mesh hole 19 of the ground layer 18.
By setting an appropriate ratio to the wiring layer 15.1
6, the delay amount is 10 to 20 psec per wiring layer 1an.
This makes it possible to give the signal a correspondingly larger signal propagation delay time.

Therefore, in the logic circuit shown in FIG.
The X wiring layer (first wiring layer) 15 and Y wiring layer of this multilayer polyimide thin film wiring board are used as wiring layers connecting between
Using the wiring layer (second wiring layer) 16, RAM 30 and L
If the X wiring layer (third wiring layer) 21 and the Y wiring layer (fourth wiring layer) 22 are used as the wiring layer connecting between the SIs 32, RA can be realized without providing a dummy gate or an extension wiring layer.
The signal transmitted through the wiring layer connecting between M30 and LSI 31 is delayed by the signal propagation delay time of the wiring layer connecting RAM 30 and LSI 32.
The data (2) propagated from the LSI 31 and the data (2) propagated from the LSI 32 can be combined. Further, the signal propagation delay time per unit length becomes large, and the density of the wiring board can be increased.

FIGS. 8 and 9 show other embodiments of the multilayer polyimide thin film wiring board of the present invention.

In this embodiment, the signal propagation is attempted to be adjusted as shown in FIG. A Y wiring layer (second wiring layer) is provided on any position where the mesh hole 13 of the ground layer 12 is formed in accordance with the delay time via a synthetic resin layer 14a made of a polyimide layer, and also extends in the Y direction. 16 is provided via a synthetic resin layer 14b made of a polyimide layer on any position of the ground layer 12 where the mesh hole 13 is formed in accordance with the signal propagation delay time to be adjusted as shown in FIG. It is something that

Also in the case of a multilayer thin film substrate with such a configuration, the wiring layers 15 and 16
is a signal corresponding to the area of the wiring layer 15 and 16 intersecting the mesh hole 13 under the influence of the dielectric substrate 11 made of a ceramic substrate having a larger dielectric constant than the synthetic resin layers 14a and 14b made of polyimide layers. A propagation delay time is given to the signal.

Therefore, the signal propagation delay time of the wiring layers 15 and 16 can be set to an arbitrary value, and the signal propagation delay time per unit length is increased, so that the density of the wiring board can be increased.

In the above embodiment, the dielectric substrate with a large dielectric constant is
Although a ceramic substrate is used, other materials with a large dielectric constant, such as glass silicon, can also be used. Further, as the synthetic resin layer, a synthetic resin layer other than the polyimide layer is also used.

Furthermore, the shape of the mesh hole in the ground layer is not limited to an ellipse.

〔Effect of the invention〕

As described above, the present invention allows mesh holes in a ground layer provided in contact with a dielectric substrate to be made to any size in accordance with the signal propagation delay time to be adjusted in a wiring layer, or The first X.

By providing mesh holes in the ground layer at arbitrary positions to match the signal propagation delay time to adjust the Y wiring layer, it is possible to eliminate unnecessary dummy gates or extension wiring layers in the wiring layer. This has the effect that the signal propagation delay time can be set arbitrarily, and the density of the wiring board can be increased.

[Brief explanation of the drawing]

Fig. 1 is a diagram of the principle configuration of the present invention, Fig. 2 is a cross-sectional view of an embodiment of the present invention, Fig. 3 is a top view of the ground layer on the dielectric substrate, and Figs. 4 and 5 are the same. A top view of the X and Y wiring layers provided on the ground layer via a synthetic resin layer, Figure 6 is a top view of the connecting portion of the X and Y wiring layers, and Figure 7 is the upper ground layer. 8 and 9 show other embodiments of the present invention, FIG. 8 is a top view of an X wiring layer provided on the ground layer via a synthetic resin layer, and FIG. The figure is a top view of the Y wiring layer, and FIG. 10 is a block diagram of a conventional logic circuit. In FIG. 1, 1 is a dielectric substrate, 2.6 is a ground layer, and 3a, 3b, 3c, and 7a. 4.8 is the X wiring layer, 5.9 is the Y wiring layer, and lO is the mesh hole. b is a synthetic resin layer, Fig. Fig. Fig. Fig.

Claims (2)

[Claims] (1) A mesh-like ground layer (2) is provided on a dielectric substrate (1) with a high dielectric constant, and X, Y wiring is provided on the ground layer (2) via a synthetic resin layer (3a, 3b). Layer (4,
5), and a synthetic resin layer (3c) is provided on the wiring layer (5).
A mesh-like ground layer (6) is provided through the ground layer (6), and synthetic resin layers (7a, 7b) are similarly formed on the ground layer (6).
) in a multilayer thin film wiring board in which X, Y wiring layers (8, 9) are provided in multiple layers through a ground layer (
2) A multilayer thin film characterized in that the mesh holes (10) are arbitrarily sized to match the signal propagation delay time to be adjusted in the first X, Y wiring layer (4, 5) above the mesh hole (10). wiring board. (2) A mesh-like ground layer (2) is provided on a dielectric substrate (1) with a high dielectric constant, and X, Y wiring is provided on the ground layer (2) via a synthetic resin layer (3a, 3b). Layer (4,
5), and a synthetic resin layer (3c) is provided on the wiring layer (5).
A mesh-like ground layer (6) is provided through the ground layer (6), and synthetic resin layers (7a, 7b) are similarly formed on the ground layer (6).
), in which the first X, Y wiring layer (4, 5) on the dielectric substrate (1) is
) is provided on any position where the mesh hole (10) of the ground layer (2) is formed in accordance with the signal propagation delay time to be adjusted.